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cannon .r. moxnmn, orrmw 20ml, n. v,

COO LIHG? EXPLOSIVE SHELLS.

Specification of Letters Patent.

Ho Drawing.

,1 0 all whom, it may concern Be it known that I, ARTHUR J.-MOXHAM, a subject of the King of Great Britain, residing at New York city, county of New York and State of New York, have invented a new and useful Improvement in Cooling Explosive Shells, of which the following is a full, clear, and exact description.

In explosive shells loaded with trinitrotoluol, picric acid and other of the crystalline high explosive, one of the difficulties experienced during the cooling is the development of piping or cavitation in the explosive material. ihe ordinary method of cooling is such that the outside layer of the explosive charge cools first below the point of crystallization. l lence, a thin band of crystallized material forms in contact with the metallic part of the inside of the shell. This thin band, which incloses a body of explosive material still molten, acts as a non-conductor and retards the cooling of the interior. Even after the crystallization has reached Well Within the body of explosive material, the center core remains not only liquid, but very liquid. The final result of this method oi cooling is, as'above stated,

piping or cavitation, as it leaves a core or cavity in the center of the shell.

The object or my invention is to avoid this piping or cavitation. To this end 1 subject ashell, loaded with explosive material having a well defined melting po1nt,to two successive coolin operations. In the first operation the shell is subjected to such a temperature thatth'e entire body or" explosive material, frorn'itsouter edge to its center, will be cooled test point closel approximating, but safely above, that' o crystallization. After the entire mass of explosive material which, although it is still liquid,

has been thus uniformly cooled to nearly its freezing point, the shell is subjected to the second cooling operation, in which it is ex posed to a temperature beloyv the freezing point of the explosi e material, thus oii'ect- 'ing the uniform crystallization or solidification of'the entire body of explosive materiziii The sdcond cooling operation should. be preferably a rapid one, because the molten charge will have so increased in density that the contraction upon further cooling Will not develop pipingor cavities.

; The following specific example illustrates one preferred-era carrying out mygirop- Patented July 29, 1919.

application filed January is, 1918. Serial No. 211,038.

as applied to a shell of given size loaded with a given explosive material.

An ordinary 155 millimeter shell. (which is approximately a six inch shell) is loaded with about fifteen and one-halfpounds of trinitrotoluol. This explosive has a melting point varying from 76 C. to 81 C, according to the specifications under Which it is manufactured. The shell, after the molten charge of trinitrotoluol is poured in, is in sorted in a container and subjected to a temperature a very few degrees above the melting 'point of the trinitrotoluol; say about 85 C. Suitable provision should be made for carrying oil the heat given up by the shell during the cooling operation. This, may be effectively done by employing, as a containena tunnel of considerable length, the shell being kept traveling therethrough slowly and a current of air of a temperature of about 85 C. caused'to circulate through the tunnel to carry off the abstracted heat.

After the molten charge of trin'itrotoluol has been reduced, by passage through the tunnel, to a uniform temperature of (say) 85 (1., the shell is immediately transferred to another cooling chamber in Which is maintained a temperature below the pointo'r crystallization of the trinitrotoluol. The result is that crystallization of the central core will take place contemporaneously or nearly so with the crystallization in the outer band and the action will be substantially uniform throughout the mass, which uniformity 01 action prevents the development of piping or cavitation.

It will be understood that the'example given is illustrative only, and that the proc ess is not dependent for its successful exe-' cution upon ;heemployment of any particular cooling appan tus. Thus it may be found practicable to cool the explosive material down to nearly its freezing point before charging it into the shell and to subject the shell itself to only the second of the two cooling operations described.

' Having now fully described my invention;- what I claim and desire to protect by Letrs Patentis:

1. The process of treating high explosive 'material of shells to effect cooling or solidi- -fication While, preventing piping or cavita- I tion, which consists in reducing the temperature-of the entire body of explosive maiorihh-to a point approxmiating, but above,

its point 'of er} its point ex flosive and then the"entire bed; of cxplosive material to a temperature below its poiniof crystallizm tion.

'2. The process of fenial oi shelle i: ei'rece ti while prevc, which consists in treating explosive macooling or solidificaiiping or cavitation, ling said material to a :tempe 1 hating but above, its pom; ol' s llizaeion effect a substan--' tlally u orm-reductn-m of its temperature i n'eve'ntin inin or cavitatioin which c0no l a:

above the point of solidification until the entire body ,thereof has been sub ected to a substantial contraction of volume and reduct-ion of temperature While maintainii'zg in a. liouidcondition the'entire body of the cooling: the material c0mparatively quickly to effect "llhe solidification of substantially the entire body of explo sive material.

l. The process of treating-shells c0nta1ning high explosive material which consists ts" i cooling ehe material at a temperature in loading the shells with the high cxplc sive in a liquid conditioin then subjecting the loaded shells to a temperature substain Sially below that of the explosive when charged until the entire body of the explosive is reduced to a temperature approximating, but, above, its freezing poinl', and then subjecting the loaded and cooled shells to a temperature subslantiall below the freezing point of the explosive When-h the formation of a band of erysatallin explosive material surrounding a molten interior is avoided and the solidification of the en tire body of explosive elfcctedwith substai'ltial thoroughness and uniformity.

5. The process of treating high explosive material of shells to veffect crystallization While preventing piping or cavitation which consists in reducing the temperature of the entire mass of explosive material until the entire mass approximates, but does notv reach, the len'iperature at which it crystallizes, and then uniformly and simultaneousl crystallizing the mass" throughout by subjecting it to a temperature below its temperature of crystallization.

In testnnonyoil' which invention I have hereunto sen my hand at New York. N. l.,

.on this 7th day of January, 1918.

ARTHUR J. MOXl-IAM 

